This article examines the development of the federal coercion power of the U.S. government during the period from the Declaration of Independence to the Civil War. Although unhappy with the states’ defiance of federal requisitions, the Founders agreed at the Constitutional Convention that the national government should not have the power to coerce individual states militarily to force them into compliance with federal law. Instead, a federal judiciary was created to uphold the supremacy of the Constitution. As part of the new constitutional makeup, the federal government now had the power to coerce individuals, rendering the coercion of states unnecessary. However, in the pre-Civil War era, federal law was frequently disregarded by certain states. The question hence became whether the federal government could de facto coerce states by coercing individuals. These debates intensified during the South Carolina Nullification Crisis, and culminated on the eve of the Civil War, as the southern states declared their intent to secede from the Union. These multiple instances of state defiance and the eventual use of federal coercive force consolidated the new constitutional arrangement. The emergence of a distinctly national constitutional identity thus paralleled the evolution of the federal power of coercion.